The effects of 2 irrigation intervals (If1: 7 days and If2: 14 days), 4 nitrogen doses (Ng, N0, N1, N2 and N3) and 2 crop coefficients (Kpc1: 0.60 and Kpc2: 0.90) on pistachio nut fertigation were studied to establish suitable irrigation and fertigation scheduling. The nitrogen levels were 0, 10, 15 and 20 mg L-1. In the traditional treatment, Ng, each tree received 500/600/400 g of NPK fertilizer at the beginning of February. Other fertilizer doses were applied in the irrigation water through a drip system. Irrigation water amount was calculated based on Class A-Pan evaporation. Wetted percentage in each irrigation was 30%. Irrigation treatments were watered 15(I1) and 8(I2) times in both years based on the irrigation intervals. Irrigation depths ranged from 324 to 907 mm for the wetted area in 2001 and from 311 to 837 mm in 2002. Evapotranspiration for the corresponding areas ranged from 586 mm to 1133 mm and 721 mm to 1212 mm for the 2001 and 2002 growing season, respectively. The maximum nitrogen amount (18.1 g m-2 in 2001 and 15.9 g m-2 in 2002) was applied to the treatment with high nitrogen and high water (If1N3Kpc2). In 2001, all pistachio trees received 4.9 and 3.2 g m-2 phosphorous and potassium while in 2002 these values decreased to 4.2 and 2.8 g m-2. The maximum yields were harvested from If2N3 with an average of 11.7 kg per tree in 2001 and from If1N0 with an average of 11.6 kg per tree in 2002.

The effects of 2 irrigation intervals (If1: 7 days and If2: 14 days), 4 nitrogen doses (Ng, N0, N1, N2 and N3) and 2 crop coefficients (Kpc1: 0.60 and Kpc2: 0.90) on pistachio nut fertigation were studied to establish suitable irrigation and fertigation scheduling. The nitrogen levels were 0, 10, 15 and 20 mg L-1. In the traditional treatment, Ng, each tree received 500/600/400 g of NPK fertilizer at the beginning of February. Other fertilizer doses were applied in the irrigation water through a drip system. Irrigation water amount was calculated based on Class A-Pan evaporation. Wetted percentage in each irrigation was 30%. Irrigation treatments were watered 15(I1) and 8(I2) times in both years based on the irrigation intervals. Irrigation depths ranged from 324 to 907 mm for the wetted area in 2001 and from 311 to 837 mm in 2002. Evapotranspiration for the corresponding areas ranged from 586 mm to 1133 mm and 721 mm to 1212 mm for the 2001 and 2002 growing season, respectively. The maximum nitrogen amount (18.1 g m-2 in 2001 and 15.9 g m-2 in 2002) was applied to the treatment with high nitrogen and high water (If1N3Kpc2). In 2001, all pistachio trees received 4.9 and 3.2 g m-2 phosphorous and potassium while in 2002 these values decreased to 4.2 and 2.8 g m-2. The maximum yields were harvested from If2N3 with an average of 11.7 kg per tree in 2001 and from If1N0 with an average of 11.6 kg per tree in 2002.